Google yesterday apologised to Gmail users whose email was out of action for more than a day.

The world’s largest ad broker confirmed in a Google Apps discussion forum late Thursday it was restoring the service for a “small number” of peeps affected by the outage.

Unsurprisingly, it didn’t reveal how many people were unable to access their email via the web-based service.

"We know how important Gmail is to our users, so we take issues like this very seriously, and we apologise for the inconvenience," said Google late yesterday.

Although most Gmail users access the service for free, some Google Apps Premier Edition customers actually pay for Google's email system.

The company has since confirmed that it has fixed the email FAIL.

“The problem with Gmail should now be resolved. We apologise for the inconvenience and thank you for your patience and continued support,” it said. “Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better.”

It remains unclear how many paying Google Apps Premier Edition customers were unable to access their Gmail during the downtime cockup.

One frustrated customer hit out at Google’s suggestion that the problem was a “temporary error”.

"This is not a temporary problem if it lasts this long. It is frustrating to not be able to expedite these issues," he said.

“This is considered a mission-critical issue here. We may have to make other arrangements. Apparently Google mail is not very reliable. I think I would have pushed for something else before we switched if I had known the level of unreliability.”

Meanwhile, Google is keeping schtum on what exactly happened to cause Gmail to fall out of its much-trumpeted cloud. ®